In vitro toxicity assessment of hydrogel patches obtained by cation‐induced cross‐linking of rod‐like cellulose nanocrystals

Abstract

With the purpose of designing active patches for photodynamic therapy of melanoma, transparent and soft hydrogel membranes (HMs) have been fabricated by cation‐induced gelation of rod‐like cellulose nanocrystals (CNCs) bearing negatively charged carboxylic groups. Na+, Ca2+, Mg2+ have been used as cross‐linkers of cellulose nanocrystal (CNC). The biosafety of this material and of its precursors has been evaluated in vitro in cell cultures. Morphological changes, cell organelles integrity, and cell survival with the tetrazolium salt reduction (MTT) assay were utilized as tests of cytotoxicity. Preliminary investigation was performed by addition of the hydrogel components to the cell culture medium and by incubations of the CNC‐HM in direct and indirect contact with a confluent monolayer of A375 melanoma cells. Direct contact assays suffered from interference of physical stress. Careful evaluation of cytotoxicity was obtained considering the overall picture provided by microscopy and biochemical tests performed with the CNC‐HM in indirect contact with two melanoma cell lines (A375, M14) and human fibroblasts. CNCs have been demonstrated to be a safe precursor material and CNC‐HMs have a good biocompatibility provided that the excess of cations, in particular of Ca2+ is removed. These results indicate that CNC and can be safely used to fabricate biomedical devices such as transparent hydrogel patches, although attention must be paid to the fabrication procedure.

Cellulose Nanocrystals/Chitosan-Based Nanosystems: Synthesis, Characterization, and Cellular Uptake on Breast Cancer Cells

“…This confirms without a doubt that the three CNCs/FA-CS-FITC nanosystems are non-cytotoxic to the MDA-MB-231 cells at concentrations below 200 µg mL −1 , with an in vitro cell viability quite above the 70% threshold [57]. These results are similar to those reported for other CNCs-based nanosystems with other tumor cell lines, such as the human breast adenocarcinoma MCF-7 cell line [58], and the A375 and M14 cells (malignant melanoma cell lines) [59].…”

On the toxicity of cellulose nanocrystals and nanofibrils in animal and cellular models

“…, Mg 2? as gelling cations was developed to use in active patches for photodynamic therapy of melanoma (Meschini et al 2019). The cytotoxicity evaluation (MTT, morphological changes, organelles integrity) using two cell lines of melanoma and one cell line of human primary dermal fibroblasts exposed to the CNC membrane by direct and indirect contact tests demonstrated this hydrogel biocompatibility.…”

Advanced Functional Materials Based on Nanocellulose for Pharmaceutical/Medical Applications

“…The percentage of cells spread was higher for Fe 3+ crosslinked gels compared to the Ca 2+ gels (except for the Ca 2+ gel with covalently attached PF), possibly due to the increased hydrophobicity and greater adsorption of serum proteins. However, this behavior can also be attributed to the certain toxicity of calcium ions, proven in a recent study by Meschini et al [ 118 ], where Ca 2+ was used as a gelling agent of negatively charged cellulose nanocrystals along with natrium and magnesium ions. However, as mentioned in the study, this high toxicity can be avoided if the excess of calcium cations from hydrogels are removed by appropriate rinsing or soaking treatments, and more attention is paid to the manufacturing process.…”

“…Considering the toxicity evaluation performed on various CNC materials (wood and non-wood), it was observed that most of the studies indicate low or even negligible cytotoxic effects [ 118 , 133 , 138 , 161 , 179 ]. However, there are also some studies in literature that record a cytotoxic effect of CNC [ 179 , 180 , 183 , 195 ].…”